An ancient Mayan text captured the moment when a royal astronomer made a scientific discovery about the movement of Venus across the night sky. The text, called the Dresden Codex, contains laborious measurements of the rising and setting of Venus. Based on these recordings, historians can now place this astronomer within a 25-year span within the first half of the 10th century. “We can see the moment when this person puts it all together,” said Gerardo Aldana, a science historian in the Department of Chicano Studies at the University of California, Santa Barbara and a co-author of a new study describing the findings.
The Dresden Codex is a gorgeous Mayan text of 39 double-sided pages with a murky and fascinating backstory. The document somehow made it out of the Yucatan Peninsula and into the Royal Library in Dresden, Germany by the 1730s, according to the Foundation for the Advancement of Mesoamerican Studies. Then, in the late 1800s, Ernst Förstemann, a German mathematician with no background in Mayan history or culture, came upon a table of Mayan numerals on page 24 of the codex. Förstemann deduced that the table contained measurements pertaining to Venus, even though no one at the time could decipher Mayan hieroglyphics.
Then, in the 1920s, chemical engineer John Teeple looked more carefully at the numbers and realized that the Maya were using a sophisticated technique to correct for the shift in their calendar caused by the irregular cycle of Venus, Aldana said.